How to Disinfect Granite and Other Natural Stone

In this continually changing landscape of health concerns, it's more important than ever to stay informed on best health practices -- especially when dealing with food-prep surfaces such as your countertops. When it comes to natural-stone surfaces in particular, there are more considerations in terms of cleaning, disinfecting and caring for than with other materials. Stone like granite, marble and travertine is naturally porous and sensitive to acidic chemicals, requiring more specific care to not only disinfect, but to keep looking its best in the process. So, let's get into these considerations for how to keep your stone clean and safe while properly maintaining your investment.

The Difference Between Cleaning and Disinfecting:

The CDC makes an important distinction between cleaning and disinfecting as sanitizing measures. Cleaning physically removes germs and potential organic material for bacteria to grow on, reducing their numbers on the surface. Disinfecting, on the other hand, is taking measures to kill the germs that are left after cleaning. It’s important to note that the CDC states doesn’t necessarily clean dirty surfaces or remove germs, but by killing germs on a surface after cleaning, it can further lower the risk of spreading infection. The CDC recommends both processes to help the spread of infectious disease.

You can read the CDC’s guide on the topic here: https://www.cdc.gov/coronavirus/2019-ncov/prepare/cleaning-disinfection.html To keep your countertops free of viruses and bacteria, it's important to always wipe away food spills and soil when they happen. This also helps to maintain your stone's protective seal and prevents acidic substances from damaging the surface.

For a daily sanitizing routine:

1. Clean the surface with a stone-safe cleaner to clear all liquids and soil
2. For disinfecting – we recommend MicroGold® Multi-Action Disinfectant Antimicrobial Spray. It’s a sister brand of Granite Gold®; it kills 99.9% of viruses and bacteria, and has been tested and proven effective to kill the COVID-19 virus. It’s safe for use on sealed stone surfaces.
3. Allow the solution to sit on the surface for 3 minutes to kill viruses; 10 minutes for bacteria.
4. Make sure to maintain a proper seal on the surface

Be Careful with Household Cleaners on Stone:

There are a few issues with most household cleaners to be aware of in terms of use on natural stone. Chemicals with high acidity will eat away at the protective seal and can chemically etch the surface of your stone - even to the point of needing professional restoration work to correct. This includes things like vinegar, lemon, orange and ammonia. With dish soaps like outlined in the instructions above, they aren't necessarily damaging to stone, but feature tallows that leave streaks, and can build up to a gradual hazing on the surface of your countertops. That's why it's important to follow up the disinfecting with a cleaner that is formulated specifically for use on natural stone that will remove those streaks, and not damage your stone's seal in the process.

Maintain Your Stone's Protective Seal

Your stone was given a protective seal when it was installed, and that needs to be maintained as your countertops go through daily use. In general, it is recommended to reseal your countertops every 6-12 months, but that is variable upon how much use the surfaces see, as well as the porosity of your stone specifically. The water test is important for determining whether your stone needs to be resealed or not. This can be done with water on various sections of your countertop (especially in areas that see heavy use). Pour water in various locations of your countertop about 3 inches in diameter and let it sit for 30 minutes before wiping it dry (though you may see a reaction before then). If the granite has darkened in the area where the water was, then it's time to reseal the surface.

How to Seal Your Stone

Make sure to clean and clear the surface with a stone-safe cleaner to make sure there is nothing in the way to prevent the seal from taking hold. We advise that sealing should be done in roughly 3-foot sections at a time. Spray your stone sealer evenly over the designated section (without completely saturating the area) and immediately work the solution into the stone with a microfiber cloth. It's important to not allow the sealer to dry on the surface, as this can lead to hazing in those areas. Next, buff the area with a fresh microfiber cloth and give the surface about 20 minutes, or until it's dry to the touch between applications. For best results, repeat the process 2-3 times.

Maintaining Your Stone's Seal

Always use pH neutral cleaners that are formulated specifically for use on natural stone where possible, and always be diligent about wiping up food and other liquid spills. It's also important to avoid cleaning implements that are overly abrasive, as these will wear the sealer away. This includes steel wool, scouring pads and gritty cleaning products that aren't made with stone in mind. It's also a good idea to keep liquid containers off your countertops, like soap dispensers, cooking oil and toiletry items. These can leave rings of buildup underneath them, allowing the chemicals to eat away at the protective seal, and in the case of oil, can seep beneath the surface to leave a difficult to remove stain. Have more questions or concerns on how best to disinfect or care for your natural stone? With decades of stone-care experience under our belts, we have tons of resources available for additional reading.

To talk to one of our stone-care experts, feel free to reach out to us at 1-800-475-STONE with your questions. Also, be sure to check out our full range of natural-stone safe products to keep your home clean and protected the right way.